From f7c06785d08156320836ee94552e7f89e1542647 Mon Sep 17 00:00:00 2001 From: Zack Rusin Date: Thu, 18 Jul 2013 03:32:02 -0400 Subject: [PATCH] gallivm: add a log function that handles edge cases Same as log2_safe, which means that it can handle infs, 0s and nans. Signed-off-by: Zack Rusin Reviewed-by: Jose Fonseca Reviewed-by: Roland Scheidegger --- src/gallium/auxiliary/gallivm/lp_bld_arit.c | 17 +++++++++++++++++ src/gallium/auxiliary/gallivm/lp_bld_arit.h | 4 ++++ 2 files changed, 21 insertions(+) diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.c b/src/gallium/auxiliary/gallivm/lp_bld_arit.c index 2ce287f938a..98409c3be86 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_arit.c +++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.c @@ -3080,6 +3080,7 @@ lp_build_exp(struct lp_build_context *bld, /** * Generate log(x) + * Behavior is undefined with infs, 0s and nans */ LLVMValueRef lp_build_log(struct lp_build_context *bld, @@ -3094,6 +3095,22 @@ lp_build_log(struct lp_build_context *bld, return lp_build_mul(bld, log2, lp_build_log2(bld, x)); } +/** + * Generate log(x) that handles edge cases (infs, 0s and nans) + */ +LLVMValueRef +lp_build_log_safe(struct lp_build_context *bld, + LLVMValueRef x) +{ + /* log(2) */ + LLVMValueRef log2 = lp_build_const_vec(bld->gallivm, bld->type, + 0.69314718055994529); + + assert(lp_check_value(bld->type, x)); + + return lp_build_mul(bld, log2, lp_build_log2_safe(bld, x)); +} + /** * Generate polynomial. diff --git a/src/gallium/auxiliary/gallivm/lp_bld_arit.h b/src/gallium/auxiliary/gallivm/lp_bld_arit.h index 6b9e0d1caf6..35119d18f7b 100644 --- a/src/gallium/auxiliary/gallivm/lp_bld_arit.h +++ b/src/gallium/auxiliary/gallivm/lp_bld_arit.h @@ -291,6 +291,10 @@ LLVMValueRef lp_build_log(struct lp_build_context *bld, LLVMValueRef a); +LLVMValueRef +lp_build_log_safe(struct lp_build_context *bld, + LLVMValueRef a); + LLVMValueRef lp_build_exp2(struct lp_build_context *bld, LLVMValueRef a); -- 2.30.2